When the uterus contracts during labor, pain travels from the uterus via the nerves in your spine (back bone as shown in the figure below) to the brain producing discomfort as shown in the figure below.

Each woman's labor is unique. The amount of pain that you experience is dependent on many different factors, which include

the size of the baby

the position of the baby

the dimensions of your pelvis

the strength of the contraction

your previous experience and expectations

many issues not yet understood

Therefore, it is hard to predict how much pain you will have until you go through labor. Some women have tolerable, controllable levels of pain, while others may benefit from some form of pain relief. Many non-medical techniques exist that can help the pain during labor, including breathing and relaxation techniques, warm showers, massage, supportive nursing care, position changes (standing, sitting, walking, rocking), and using a labor ball to name a few. A birthing educator can help you with more information. However, for some women, these measures may not be enough.